3504 results about "End-group" patented technology

Polyimide sulfone resins are provided with a glass transition temperature of from 200–350° C., residual volatile species concentration of less than 500 ppm and a total reactive end group concentration of less than about 120 milliequivalents / kilogram resin. The resins have high heat capability and good melt stability. Methods to prepare the said resins and articles made from the resins are also provided.

Main chain thermotropic liquid crystal esters, ester-imides, and ester-amides were prepared from AA, BB, and AB type monomeric materials and were end-capped with phenylacetylene, phenylmaleimide, or nadimide reactive end-groups. The resulting reactive end-capped liquid crystal oligomers exhibit a variety of improved and preferred physical properties. The end-capped liquid crystal oligomers are thermotropic and have, preferably, molecular weights in the range of approximately 1000-15,000 grams per mole. The end-capped liquid crystal oligomers have broad liquid crystalline melting ranges and exhibit high melt stability and very low melt viscosities at accessible temperatures. The end-capped liquid crystal oligomers are stable for up to an hour in the melt phase. These properties make the end-capped liquid crystal oligomers highly processable by a variety of melt process shape forming and blending techniques including film extrusion, fiber spinning, reactive injection molding (RIM), resin transfer molding (RTM), resin film injection (RFI), powder molding, pultrusion, injection molding, blow molding, plasma spraying and thermo-forming. Once processed and shaped, the end-capped liquid crystal oligomers were heated to further polymerize and form liquid crystalline thermosets (LCT). The fully cured products are rubbers above their glass transition temperatures. The resulting thermosets display many properties that are superior to their non-end-capped high molecular weight analogs.

An optical cable, which is flame-retardant, and has excellent adhesion of the protective covering to the fiber cladding and uniform thickness of the fiber cladding, contains a polymer optical conductor containing a fiber core; a single-layer or multi-layer fiber cladding; an inner external layer which adheres to the fiber cladding with a peel force of at least 50 N; and an outer external layer which adheres to the inner external layer with a peel force of not more than 30 N. The inner external layer contains a molding composition having a first polyamide selected from a) PA 11, b) PA 12, c) PA 1012, d) PA 1212, e) a copolyamide of at least two of PA 11, PA 12, PA 1012 and PA 1212, said copolyamide containing not more than 30 mol % of a comonomer, and f) mixtures thereof. The first polyamide contains at least 50 mueq / g of amino end groups. The first molding composition has a zero-shear viscosity of from 400 to 6000 Pas. The outer external layer contains a second molding composition which has the following i)-iii): i) from 20 to 95% by weight of a second polyamide selected from a) PA 11, b) PA 12, c) PA 1012, d) PA 1212, e) a copolyamide of at least two of PA 11, PA 12, PA 1012 and PA 1212, said copolyamide containing not more than 30 mol % of a comonomer, f) a polyetheramide of at least one of a)-e), and g) mixtures thereof, ii) from 5 to 45% by weight of a flame retardant, and iii) from 0 to 60% by weight of an impact modifier.

In one aspect, the present disclosure encompasses polymerization systems for the copolymerization of CO2 and epoxides comprising 1) a catalyst including a metal coordination compound having a permanent ligand set and at least one ligand that is a polymerization initiator, and 2) a chain transfer agent having two or more sites that can initiate polymerization. In a second aspect, the present disclosure encompasses methods for the synthesis of polycarbonate polyols using the inventive polymerization systems. In a third aspect, the present disclosure encompasses polycarbonate polyol compositions characterized in that the polymer chains have a high percentage of —OH end groups and a high percentage of carbonate linkages. The compositions are further characterized in that they contain polymer chains having an embedded polyfunctional moiety linked to a plurality of individual polycarbonate chains.

The present invention pertains to polyisobutylene urethane, urea and urethane / urea copolymers, to methods of making such copolymers and to medical devices that contain such polymers. According to certain aspects of the invention, polyisobutylene urethane, urea and urethane / urea copolymers are provided, which comprise a polyisobutylene segment, an additional polymeric segment that is not a polyisobutylene segment, and a segment comprising a residue of a diisocyanate. According to other aspects of the invention, polyisobutylene urethane, urea and urethane / urea copolymers are provided, which comprise a polyisobutylene segment and end groups that comprise alkyl-, alkenyl- or alkynyl-chain-containing end groups.

A method for end-capping polycarbonate resins, comprising the step of processing a mixture comprising a polycarbonate having free hydroxyl-end groups and an end-capping reagent in a melt transesterification reaction to produce a polycarbonate resin, wherein the end-capping reagent comprises a mixture of: (a) at least one species of a symmetrical activated aromatic carbonate, and (b) at least one species of an optionally-substituted phenol, whereby said end-capping reagent reacts with at least some of the free hydroxyl end-groups of the polycarbonate to produce an end-capped polycarbonate resin.